某院鲍曼不动杆菌流行克隆株的分子特征

Molecular Epidemiology Characteristics of Acinetobacter Baumannii Strains in One Hospital

目的了解临床分离鲍曼不动杆菌的主要流行克隆株的变化趋势,揭示其分子流行的主要特征。方法筛选解放军253医院2010年6月—2012年12月临床分离的74株不重复鲍曼不动杆菌作为实验菌株,应用基于序列分型的多重聚合酶链反应(PCR)方法鉴定鲍曼不动杆菌的主要流行克隆谱系;利用限制性内切酶ApaI对实验菌株基因组DNA进行酶切和脉冲场凝胶电泳(PFGE)分析,并利用BioNumerics软件进行聚类分析;应用PCR及测序方法检测10种耐药相关基因(blaOXA-51-like、blaOXA-23-like、blaOXA-24-like、blaOXA-58-like、blaTEM、blaampC、armA、ISAba1、intI 1和intI 2)的携带情况。结果本组实验菌株克隆谱系以Group 1序列型为主,所占比例高达77.0%;PFGE带型表现出多样性,可大致分为13种图谱,其中主要型别为A型(35株);耐药相关基因blaOXA-51-like、blaOXA-23-like、blaTEM、blaampC、armA、ISAba1和intI 1的阳性率分别为100.0%、54.1%、86.5%、66.2%、89.2%、90.5%和85.1%,未检出blaOXA-24-like、blaOXA-58-like和intI 2。结论该院临床分离的鲍曼不动杆菌存在主要流行克隆株,与欧洲克隆谱系Ⅱ具有高度的同源性;多重耐药相关基因的携带率较高;不同的序列型或PFGE型别中存在同一耐药基因交叉分布的现象,说明多种耐药相关基因在鲍曼不动杆菌中发生着水平转移。

Objective To study the change trend of main clonal strains of acinetobacter baumannii isolates in or- der to discover the molecular epidemiology characteristics. Methods Seventy-four different aeinetohaeter Baumannii strains isolated in clinical department during June 2010 and December 2012 were selected, and main clonal lineages were detected with multiplex polymerase chain reaction （PCR） based on sequence groups; strains of genome DNA were ana- lyzed with endonuclease and pulsed field gradient gel electrophoresis （PFGE） based on restrictive endonucleases ApaI, and cluster analysis was carried out by BioNumerics software; 10 resistance genes of blaOXA-51-1ike, blaOXA-23-1ike, blaOXA-24-1ike, blaOXA-58-1ike, blaTEM, blaampC, armA, ISAbal, intI 1 and intI 2 isolates were detected with PCR and sequencing method. Results The main clonal lineages was sequence group 1 （77.0%） ; band forms of PFGE were diversified, and were roughly classified into 13 genotypes, in which type A （n = 35） was the main group; the positive rates of resistance genes of blaOXA-51-1ike, blaOXA-23-1ike, blaTEM, blaampC, armA, ISAbal and intI 1 were 100.0%, 54.1%, 86.5%, 66.2% , 89.2% , 90.5% and 85.1% respectively, but blaOXA-24-1ike, blaOXA-58-1ike and intI 2 were not detected. Conclusion The main prevalent clonal lineages exist in isolated Acinetobacter baumannii in the hospital, which may have high homology with European clonal lineage I1 ; detection rate of related genes of multidrug resistant is high ; the same resistant gene exists within genotypically unrelated strains, therefore it is proven that antibiotic resistance genes are readily exchanged between cocirculating strains in genotypically distinguishable strains.